EP0123946A1 - Reproducing rate control apparatus for information recording disc - Google Patents
Reproducing rate control apparatus for information recording disc Download PDFInfo
- Publication number
- EP0123946A1 EP0123946A1 EP84103636A EP84103636A EP0123946A1 EP 0123946 A1 EP0123946 A1 EP 0123946A1 EP 84103636 A EP84103636 A EP 84103636A EP 84103636 A EP84103636 A EP 84103636A EP 0123946 A1 EP0123946 A1 EP 0123946A1
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- EP
- European Patent Office
- Prior art keywords
- revolution number
- disc
- information
- control apparatus
- rate control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 230000000694 effects Effects 0.000 claims description 2
- 230000010354 integration Effects 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 12
- 230000001172 regenerating effect Effects 0.000 description 6
- 238000001514 detection method Methods 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000881 depressing effect Effects 0.000 description 1
- 230000000063 preceeding effect Effects 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
- G11B19/24—Arrangements for providing constant relative speed between record carrier and head
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
- G11B19/28—Speed controlling, regulating, or indicating
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
- G11B20/10527—Audio or video recording; Data buffering arrangements
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B21/00—Head arrangements not specific to the method of recording or reproducing
- G11B21/02—Driving or moving of heads
- G11B21/08—Track changing or selecting during transducing operation
- G11B21/081—Access to indexed tracks or parts of continuous track
- G11B21/083—Access to indexed tracks or parts of continuous track on discs
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
- G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
- G11B27/19—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier
- G11B27/28—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording
- G11B27/32—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording on separate auxiliary tracks of the same or an auxiliary record carrier
Definitions
- This invention relates to a reproducing rate control apparatus for an information recording disc in which pieces of information are, along with the absolute times for respective information pieces to start (representative of the reproduction time measured from the innermost circumference of the information recording disc), recorded on the disc at a constant linear velocity.
- Fig. 1 is a block diagram showing a prior art signal reproducing rate control apparatus for a digital audio disc (DAD).
- DAD digital audio disc
- a constant linear velocity (CLV) scheme is adopted wherein the signal recording rate is constant at inner and outer circumferential positions of the disc. Accordingly, the revolution number of a motor 2 is changed with the read position of an information reader 32 adapted to read information recorded on the disc.
- the information reader 32 is fixed on a carriage 33 and as the carriage 33 is driven by a motor 34, the information reader 32 is moved in parallel to the disc 1.
- the motor 34 is rotated at a constant speed by means of a drive circuit 35 and the parallel movement of the information reader 32 is directed toward the outer circumference of the disc 1 when a switch 36 is transferred to a contact a as shown in Fig. 1 and directed toward the inner circumference of the disc 1 with the switch 36 transferred to a contact b.
- a synchronizing signal detecting and regnerating circuit 3 detects a synchronizing signal contained in a signal read out of the disc 1 and produces a synchronizing signal pulse. In the event of loss of the synchronizing signal due to, for example, a scratch on the disc 1, this circuit 3 also functions to generate a pulse which supplements the synchronizing signal at a position where the synchronizing signal is originally scheduled to take place.
- a recording modulation scheme used imposes restrictions on the regeneration range of the synchronizing signal produced from the synchronizing signal detecting and regenerating circuit 3.
- a regeneration range will be explained by taking a modulation scheme as shown in Figs. 2A and 2B, for instance.
- the modulation scheme though its details are not described herein, it is prescribed that 4.3218 MHz is used as a reference clock frequency. Therefore, the clock period, designated by T, is and the information is recorded on the basis of pulses having widths ranging from 3T to 11T as shown in Fig. 2A.
- the synchronizing signal detecting and regenerating circuit 3 is responsive to the clock signal to count a read-out signal so as to exactly discriminate a 11T signal from a 3T, 4T, 5T, ... or 10T signal to regenerate a synchronizing pulse signal as shown in Fig. 2B.
- the 11T signal For discrimination of the 11T signal from the 10T signal having a pulse width which is the closest to that of the 11T signal, the 11T signal must have a duration of 10.5T or more.
- the synchronizing signal is allowed to have a tolerance of , i.e., ⁇ 4.5%.
- a frequency-voltage converter (hereafter referred to as F-V converter) 6 counts the synchronizing signal frequency and provides a voltage in accordance with a count value.
- An error amplifier 8 receives, as an input voltage, the output voltage of the F-V converter 6 via a low-pass filter 7, and a voltage in accordance with a difference between the input voltage and a reference voltage 9 is fed back to the motor 2 via a drive amplifier 10. As a result, the revolution number of the motor 2 is controlled so that the information is read out of the disc 1 at a constant rate.
- a pseudo-synchronizing signal generating circuit 5 is provided.
- a selector 4 is actuated by a discriminator 11 adapted to decide whether the synchronizing signal is detected, so as to be transferred to a contact a when starting and to a contact b under the normal operation.
- the operation of the pseudo-synchronizing signal generating circuit 5 will now be described.
- the 3T to 11T pulse width signals are involved in the modulation scheme described herein.
- the pattern "High” and “Low” or “Low” and “High” of the two successive pulses of the maximum pulse width 11T is used as the synchronizing signal and the period thereof is 588T. Accordingly, even when the synchronizing signal can not be detected, it is possible to determine the pseudo-period of the synchronizing signal by detecting the maximum pulse width and multiplying it with 588/11.
- the pseudo-synchronizing signal generating circuit 5 includes a maximum pulse width detector 12 which counts the pulse width on the basis of narrow pulses having a duration of less than at least T, so as to determine the maximum pulse width value within a fixed time interval. A value obtained from the maximum pulse width detector 12 is multiplied with 588/11 at a calculator 13 to predict the synchronizing signal period. At a pulse generator 14, the narrow pulses used for counting the pulse width are divided at a division ratio equal to a value obtained from the calculator 13 to generate the pseudo-synchronizing signal.
- the pseudo-synchronizing signal is generated by the pseudo-synchronizing signal generating circuit 5 irrespective of the relative position to the disc 1 of the information reader 32 for reading the information signal from the disc 1, to ensure that the motor 2 can be pulled into the normal rotation through a P loop to be described below.
- the components 1, 3, 6, 7, 8, 10 and 2 constitute a frequency control loop (hereinafter called P loop) which functions to reduce irregularities in rotation speed.
- P loop frequency control loop
- the revolution number of the motor 2 is determined by the reference voltage 9 but in order to assure accuracy and stability of the synchronizing signal, a phase control loop is provided in addition to the P loop.
- This phase control loop generally called an I loop, is constituted with the components 1, 3, 15, 16, 17, 18, 19, 10 and 2, in which, as will be described, the above- mentioned synchronizing signal is phase-compared with a reference signal obtained by frequency-dividing at the frequency divider 16 the output of the reference frequency oscillator 15 and a voltage corresponding to the difference as a result of the phase comparison is applied to the motor 2.
- the I loop functions to eliminate a frequency error in the revolution number of the motor 2.
- a signal produced from a reference frequency oscillator 15 is subjected to frequency division at the frequency divider 16.
- the synchronizing signal is also subjected to frequency division at a frequency divider 17 and the frequency outputs of the two frequency dividers 16 and 17 are inputted to a phase comparator 18 which, in turn, provides a voltage in accordance with a phase difference between the input signals.
- the output of the phase comparator 18 is added to the P loop via a low-pass filter 19 and then applied to the motor 2 via the drive amplifier 10. Consequently, the revolution number of the motor 2 is locked to the reference frequency of the reference frequency oscillator 15.
- Selectors 21 and 22 shown in Fig. 1 are switched over as shown in Fig. 3 by means of a system control circuit 23 comprised of, for example, a microcomputer each time the rotation made of the motor 2 changes.
- the synchronizing signal can not occur and therefore, the selector 4 associated with the pseudo-synchronizing signal generating circuit is transferred to the contact a, the selector 22 to a contact c associated with the output of the F-V converter 6, and the selector 21 to a contact g.
- the I loop can remain undisturbed before the motor 2 is pulled into the synchronizing signal detection range.
- the selector 4 is transferred to the contact b, the selector 22 to a contact d and the selector 21 to a contact e, thereby assuring the operation as described previously.
- the innermost circumference of the disc 1 contains a menu zone on which recorded are various kinds of information including the number of tunes and the absolute time for the respective tunes to start (representative of the performance time measured from the innermost circumference).
- the information reader 32 is first moved to the innermost circumference of the disc 1 to pick up the information and the thus picked up information is stored into, for example, a RAM of the system control circuit 23.
- the current absolute time is compared with an absolute time allotted to the intended tune to cause the reader 32 to be moved in accordance with a difference, thus assuring rapid accessing.
- a track servo circuit 37 for signal track following-up is required to be disconnected by transferring a selector 38 associated with the circuit 37 to a contact b, and as a result, no signal can be obtained from the disc 1 during the movement of the reader 32. Therefore, it follows that the synchronizing signal will not occur and the pseudo-synchronizing signal generating circuit will not operate correctly, giving rise to dangerous runaway of the motor speed control circuit.
- the selector 21 is transferred to a contact f (see Fig. 3) connected to an output terminal of a hold circuit 20 shown in Fig. 1 which is responsive to the system control circuit 23 to hold a revolution number immediately prior of accessing.
- the selector 22 is transferred to a contact d and the output of the hold circuit 20 is applied to the motor 2 to rotate it at a constant speed.
- the reader 32 is moved by the motor 34 and after completion of the movement, the track servo is recovered by transferring the selector 38 to a contact a so that the track servo circuit 37 can be activated. Thereafter, the selector 22 is transferred to the contact c to activate the motor speed control circuit.
- Fig. 4 shows the relation between the radius and the revolution number of the digital audio disc. At the innermost circumference measuring a radius of about 25 mm, the revolution number is about 8 rps and at the outermost circumference measuring a radius of about 60 mm, the revolution number is 3.3 rps.
- the motor servo mode is switched over as shown in Fig. 5. More particularly, the motor planetuion number allotted to the innermost circumference is held until accessing to the outermost circumference has been completed and thereafter, the motor servo mode is switched to a start mode which changes into a normal mode after a time interval T 1 .
- the proceeding enters into the random access it is examined as to what number of tune is to be accessed by reading information stored in the RAM included in the system control circuit 23. For example, a sixth tune is determined.
- a sixth tune is determined.
- the tune number to be accessed can be determined by reading the RAM.
- a travelling time for the information reader (pickup) is calculated from the command time and the current time.
- Form example, x seconds is determined.
- a current value of the revolution number of the motor for disc rotation is held.
- the track servo circuit is disconnected and the pickup is moved for x seconds. Thereafter, the track servo circuit is pulled in.
- a current value of time (absolute value) is read out of the disc when the pickup reaches a desired position. For example, a minutes and b seconds is determined.
- the absolute value is stored in the signal track.
- the track servo circuit is again disconnected and the information reader (pickup) is returned for y seconds. Thereafter, the track servo circuit is pulled in. Subsequently, the proceeding returns to the step S6 and the steps S6, S7, S8 and S9 or the steps S6, S7, S10 and Sll are executed.
- the information reader (pickup) is returned by one track.
- a current value of time (absolute time) is read out of the disc.
- the information reader (pickup) is advanced by one track.
- a current value of time is read out of the disc.
- the waiting time Tl is required for the motor servo operation, whereby after normal operation is reached, the information including the number of tunes and the absolute time is read to further correct accessing (See Figs. 5A-5D).
- This correction as will be seen from the flow chart of Fig. 6, is repeated several times. Consequently, the waiting time Tl for the motor servo operation disadvantageously occupies a large proportion within the entire access time. To reduce the access time, the waiting time Tl must be decreased.
- An object of the present invention is to provide a reproducing rate control apparatus capable of reducing the time for high rate search (random access).
- the present invention is featured by comprising means for predicting a revolution number of a disc at a command position, means for controlling a motor for rotating the disc so that the disc rotates at a predicted revolution number, and means for moving an information reader adapted to read information recorded on the disc to the command position when the revolution number controlling is effected or after the revolution number controlling has been completed, whereby high rate search (random access) for reading a desired kind of information can be effected.
- the present invention is further featured by comprising a disc drive motor revolution number detector, whereby a revolution number detected by the disc drive motor revolution number detector is compared with the predicted revolution number to effect revolution number controlling so that the former revolution number coincides with the latter revolution number.
- FIG. 7 there is illustrated a preferred embodiment of a signal reproducing rate control apparatus according to the present invention.
- components corresponding to those in Fig. 1 are designated by identical reference numerals.
- Reference numeral 24 designates a command voltage output circuit an example of which is illustrated in Fig. 8.
- a command voltage output circuit exemplified in Fig. 8 comprises a plurality of voltage sources V a to V x with preset voltages (also designated by V to V ) and a switch 25 which is controlled by a system control circuit 23.
- the system control circuit 23 includes a ROM stored with a table as shown in Table 1 below and selects a command revolution number in accordance with an absolute time allotted to a command position under random accessing.
- the preset voltages V , V b , V c , ... and V x supplied from the voltage sources V a to V x shown in Fig. 8 correspond to revolution numbers 8.0, 6.8, ... and 3.3 rps listed in Table 1.
- a motor drive voltage approximating a revolution number at a command position is selected by switching over the switch 25 and applied to a motor 2.
- a voltage corresponding to a command revolution number, for example, V is first set prior to effecting high rate search (access) and thereafter, an information reader 23 is moved for accessing. After the accessing has been completed, the motor servo mode is switched to a start mode, which is followed by a normal mode for normal rotation.
- This high rate search according to teachings of the present invention is different from the prior art high rate search described with reference to Fig. 5 in that when the start mode is reached, the revolution number has already been in close proximity of the command striguion number V co .
- a time interval T 2 required for pulling the motor servo mode into the normal mode can be reduced as compared to the time interval T 1 shown in Fig. 5.
- the time interval T 2 can be substantially zeroed if the difference from the command revolution number is allowed to fall within ⁇ 5% by increasing the number of the voltage sources shown in Fig. 8.
- the command voltage output circuit 24 may also be constituted by a well known PWM wave generator utilizing a clock pulse and a counter.
- Fig. 10 shows an example of the PWM wave generator.
- a counter 26 is set by a reference frequency and is preset by a rectangular wave having a fixed period and a duty ratio varying according to an absolute time allotted to a command position.
- a low-pass filter 19 corresponds to that shown in Fig. 7.
- a signal at a constant frequency is delivered to the low-pass filter 19.
- the duty cycle of a rectangular waveform output from the counter 26 is varied with the preset value and therefore, a voltage delivered out of the low-pass filter 19 can correspond to the command revolution number allotted to the command random accessing position.
- a flow chart as shown in Fig. 11 is illustrative of functions characteristic to the system control circuit 23 of Fig. 7 and it substitutes for the step S4 between points A and B in the Fig. 6 flow chart.
- the function of the Fig. 7 system control circuit can be described by replacing the step S4 in Fig. 6 with steps S20 to S22 in Fig. 11.
- a revolution number of the disc corresponding to 16 minutes and 00 second which is read out of the RAM in the step S2 is read out of the ROM included in the system control circuit 23. For example, 5.6 rps is thus determined.
- a value of disc motor drive voltage corresponding to the 5.6 rps revolution number is determined by reading data stored in the ROM. For example, 1.6 V is determined.
- the switch 25 in Fig. 8 is so transferred as to apply the 1.6 V voltage determined in the step S21 to the disc drive motor 2.
- Fig. 12 shows another embodiment of the apparatus according to the present invention wherein a motor revolution number detector 30 is added, with the remaining components corresponding to those in Fig. 7 designated by identical reference numerals.
- the Fig. 7 apparatus is disadvantageous in that an error in the command revolution number is caused when voltage-revolution number characteristics of the disc motor fluctuate or when the voltage-revolution number characteristics are so affected by disc load characteristics as to vary.
- Fig. 13 illustrates a command voltage output circuit 24 suitable for the Fig. 12 embodiment and Fig. 14 illustrates waveforms useful in explaining the operation of the Fig. 13 circuit.
- the command voltage output circuit 24 as shown in Fig. 13 comprises constant current sources 101 and 102, switches 103, 104 and 105 which are on-off controlled by a system control circuit 23, a capacitor 106, an operation amplifier 107, and a buffer 108.
- the motor 2 is driven by the output from the buffer 108.
- An integration amplifier comprised of the capacitor 106 and operation amplifier 107 and the two, positive and negative, constant current sources 101 and 102 constitute a ramp function generator.
- Detection data from the revolution number detector 30 shown in Fig. 12 is compared with data of a predicted command revolution number at the system control circuit 23.
- the system control circuit 23 turns on the switch 104.
- the output of the ramp function generator, i.e., of the operation amplifier 107 increases as shown in Fig. 14, which increases the revolution number of the motor 2.
- the system control circuit 23 turns off the switch 104.
- the output of the operation amplifier is maintained at a constant value.
- the switch 103 is a switch for resetting the command voltage after a random access has been finished.
- Fig. 15A shows a flow chart illustrative of functions characteristic to the system control circuit 23 of Fig. 12 and the flow chart substitutes for the steps S4 and S5 between points A and C in the Fig. 6 flow chart.
- the function of the Fig. 12 system control circuit can be described by replacing the steps S4 and S5 in Fig. 6 with steps S30 to S43 in Fig. 15A.
- Fig. 12 system control circuit 23 performs the same functions and only the steps S30 to S43 shown in Fig. 15 will be described below.
- a revolution number of the disc corresponding to an absolute time of 16 minutes and 00 second which is read out of the RAM in the step S2 is read out of the ROM included in the system control circuit 23. For example, 5.6 rps is thus determined.
- the selector 38 is transferred to contact b to disconnect the track servo circuit.
- the x seconds determined in the step S3 is inputted to a timer included in the system control circuit 23 which determines a desired travelling time of the information reader 32.
- the information reader (pickup) is moved.
- Voltage of the disc drive motor 2 is varied to change the revolution number of the motor 2.
- the track servo circuit is connected.
- the disc drive motor voltage is fixed.
- step S 39 If the proceeding proceeds to the step S 39 by way of the steps S 34 to S36, there is no chance of fixing the disc drive motor voltage. In this case, fixation of the motor voltage is carried out in the steps S41 to S43. Conversely, if the proceeding proceeds to the step S39 by way of the steps S34, S35, S37 and S38, the disc drive motor voltage is fixed in the step S37 with the result that the voltage fixation is doubled in the step S43. However, such a doubled voltage fixation arises no inconveniences in the operation.
- Fig. 16 shows still another embodiment of the apparatus according to the invention wherein a position detector 31 for the information reader is added.
- the recording linear velocity falls within a range of from 1.2 m/S to 1.4 m/S. Accordingly, in a disc having information recorded at a linear velocity of 1.2 m/S, the predicted command revolution number deviates from that pursuant to an absolute time-revolution number correspondence table established under a calculation condition of 1.4 m/S.
- the time for pulling the disc motor mode into the normal rotation after the high rate search can be minimized and hence the time for the high rate search (random access) can advantageously be minimized.
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Abstract
Description
- This invention relates to a reproducing rate control apparatus for an information recording disc in which pieces of information are, along with the absolute times for respective information pieces to start (representative of the reproduction time measured from the innermost circumference of the information recording disc), recorded on the disc at a constant linear velocity.
- Fig. 1 is a block diagram showing a prior art signal reproducing rate control apparatus for a digital audio disc (DAD).
- Referring to Fig. 1, in order to increase the recording density in a
digital audio disc 1, a constant linear velocity (CLV) scheme is adopted wherein the signal recording rate is constant at inner and outer circumferential positions of the disc. Accordingly, the revolution number of amotor 2 is changed with the read position of aninformation reader 32 adapted to read information recorded on the disc. Theinformation reader 32 is fixed on acarriage 33 and as thecarriage 33 is driven by amotor 34, theinformation reader 32 is moved in parallel to thedisc 1. Themotor 34 is rotated at a constant speed by means of adrive circuit 35 and the parallel movement of theinformation reader 32 is directed toward the outer circumference of thedisc 1 when aswitch 36 is transferred to a contact a as shown in Fig. 1 and directed toward the inner circumference of thedisc 1 with theswitch 36 transferred to a contact b. - A synchronizing signal detecting and regnerating
circuit 3 detects a synchronizing signal contained in a signal read out of thedisc 1 and produces a synchronizing signal pulse. In the event of loss of the synchronizing signal due to, for example, a scratch on thedisc 1, thiscircuit 3 also functions to generate a pulse which supplements the synchronizing signal at a position where the synchronizing signal is originally scheduled to take place. A recording modulation scheme used imposes restrictions on the regeneration range of the synchronizing signal produced from the synchronizing signal detecting and regeneratingcircuit 3. - A regeneration range will be explained by taking a modulation scheme as shown in Figs. 2A and 2B, for instance. In the modulation scheme, though its details are not described herein, it is prescribed that 4.3218 MHz is used as a reference clock frequency. Therefore, the clock period, designated by T, is
- The synchronizing signal detecting and regenerating
circuit 3 is responsive to the clock signal to count a read-out signal so as to exactly discriminate a 11T signal from a 3T, 4T, 5T, ... or 10T signal to regenerate a synchronizing pulse signal as shown in Fig. 2B. For discrimination of the 11T signal from the 10T signal having a pulse width which is the closest to that of the 11T signal, the 11T signal must have a duration of 10.5T or more. In other words, the synchronizing signal is allowed to have a tolerance ofcircuit 3 to discriminate the synchronizing signal when the synchronizing signal frequency deviates by more than ±4.5%, and thecircuit 3 then stops regenerating the signal. - Returning to Fig. 1, a frequency-voltage converter (hereafter referred to as F-V converter) 6 counts the synchronizing signal frequency and provides a voltage in accordance with a count value. An error amplifier 8 receives, as an input voltage, the output voltage of the
F-V converter 6 via a low-pass filter 7, and a voltage in accordance with a difference between the input voltage and areference voltage 9 is fed back to themotor 2 via adrive amplifier 10. As a result, the revolution number of themotor 2 is controlled so that the information is read out of thedisc 1 at a constant rate. - Since the synchronizing signal detecting and regenerating
circuit 3 is deactivated when the synchronizing signal frequency deviates by more than ±4.5% as described previously, the synchronizing signal will not be delivered out when starting. Therefore, it is necessary to generate a pseudo-synchronizing signal before the synchronizing signal detecting and regeneratingcircuit 3 is activated, thereby ensuring that the revolution number of thedisc 1 or themotor 2 can approach the normal revolution number. To this end, a pseudo-synchronizingsignal generating circuit 5 is provided. Aselector 4 is actuated by adiscriminator 11 adapted to decide whether the synchronizing signal is detected, so as to be transferred to a contact a when starting and to a contact b under the normal operation. - The operation of the pseudo-synchronizing
signal generating circuit 5 will now be described. As described previously, the 3T to 11T pulse width signals are involved in the modulation scheme described herein. The pattern "High" and "Low" or "Low" and "High" of the two successive pulses of the maximum pulse width 11T is used as the synchronizing signal and the period thereof is 588T. Accordingly, even when the synchronizing signal can not be detected, it is possible to determine the pseudo-period of the synchronizing signal by detecting the maximum pulse width and multiplying it with 588/11. - This proceeding is implemented by the pseudo-synchronizing
signal generating circuit 5. Included in thecircuit 5 is a maximumpulse width detector 12 which counts the pulse width on the basis of narrow pulses having a duration of less than at least T, so as to determine the maximum pulse width value within a fixed time interval. A value obtained from the maximumpulse width detector 12 is multiplied with 588/11 at a calculator 13 to predict the synchronizing signal period. At apulse generator 14, the narrow pulses used for counting the pulse width are divided at a division ratio equal to a value obtained from the calculator 13 to generate the pseudo-synchronizing signal. - In this manner, whenever the detection of the synchronizing signal is impossible, the pseudo-synchronizing signal is generated by the pseudo-synchronizing
signal generating circuit 5 irrespective of the relative position to thedisc 1 of theinformation reader 32 for reading the information signal from thedisc 1, to ensure that themotor 2 can be pulled into the normal rotation through a P loop to be described below. - The
components - The revolution number of the
motor 2 is determined by thereference voltage 9 but in order to assure accuracy and stability of the synchronizing signal, a phase control loop is provided in addition to the P loop. This phase control loop, generally called an I loop, is constituted with thecomponents frequency divider 16 the output of thereference frequency oscillator 15 and a voltage corresponding to the difference as a result of the phase comparison is applied to themotor 2. Thus, the I loop functions to eliminate a frequency error in the revolution number of themotor 2. - The I loop will be described below. A signal produced from a
reference frequency oscillator 15 is subjected to frequency division at thefrequency divider 16. With the view of making the frequency of the synchronizing signal coincident with the output frequency of thedivider 16, the synchronizing signal is also subjected to frequency division at afrequency divider 17 and the frequency outputs of the twofrequency dividers phase comparator 18 which, in turn, provides a voltage in accordance with a phase difference between the input signals. The output of thephase comparator 18 is added to the P loop via a low-pass filter 19 and then applied to themotor 2 via thedrive amplifier 10. Consequently, the revolution number of themotor 2 is locked to the reference frequency of thereference frequency oscillator 15. -
Selectors system control circuit 23 comprised of, for example, a microcomputer each time the rotation made of themotor 2 changes. - At the time of starting the
motor 2, the synchronizing signal can not occur and therefore, theselector 4 associated with the pseudo-synchronizing signal generating circuit is transferred to the contact a, theselector 22 to a contact c associated with the output of theF-V converter 6, and theselector 21 to a contact g. As a result, the I loop can remain undisturbed before themotor 2 is pulled into the synchronizing signal detection range. - Under the normal operation, the
selector 4 is transferred to the contact b, theselector 22 to a contact d and theselector 21 to a contact e, thereby assuring the operation as described previously. - A high rate search (random access) mode will now be described. The innermost circumference of the
disc 1 contains a menu zone on which recorded are various kinds of information including the number of tunes and the absolute time for the respective tunes to start (representative of the performance time measured from the innermost circumference). When reproducing the disc, theinformation reader 32 is first moved to the innermost circumference of thedisc 1 to pick up the information and the thus picked up information is stored into, for example, a RAM of thesystem control circuit 23. Thus, when a desired tune number is to be accessed, the current absolute time is compared with an absolute time allotted to the intended tune to cause thereader 32 to be moved in accordance with a difference, thus assuring rapid accessing. - When moving the
reader 32 for reading the information from thedisc 1, atrack servo circuit 37 for signal track following-up is required to be disconnected by transferring aselector 38 associated with thecircuit 37 to a contact b, and as a result, no signal can be obtained from thedisc 1 during the movement of thereader 32. Therefore, it follows that the synchronizing signal will not occur and the pseudo-synchronizing signal generating circuit will not operate correctly, giving rise to dangerous runaway of the motor speed control circuit. - To avoid such inconveniences, when accessing, the
selector 21 is transferred to a contact f (see Fig. 3) connected to an output terminal of ahold circuit 20 shown in Fig. 1 which is responsive to thesystem control circuit 23 to hold a revolution number immediately prior of accessing. In addition, theselector 22 is transferred to a contact d and the output of thehold circuit 20 is applied to themotor 2 to rotate it at a constant speed. Under this condition, thereader 32 is moved by themotor 34 and after completion of the movement, the track servo is recovered by transferring theselector 38 to a contact a so that thetrack servo circuit 37 can be activated. Thereafter, theselector 22 is transferred to the contact c to activate the motor speed control circuit. - Fig. 4 shows the relation between the radius and the revolution number of the digital audio disc. At the innermost circumference measuring a radius of about 25 mm, the revolution number is about 8 rps and at the outermost circumference measuring a radius of about 60 mm, the revolution number is 3.3 rps.
- When a tune recorded on the outermost circumference is desired to be accessed during performance of a tune recorded on the innermost circumference, the motor servo mode is switched over as shown in Fig. 5. More particularly, the motor revoltuion number allotted to the innermost circumference is held until accessing to the outermost circumference has been completed and thereafter, the motor servo mode is switched to a start mode which changes into a normal mode after a time interval T1.
- Referring now to a flow chart shown in Figs. 6A and 6B, functions of this prior art
system control circuit 23 will be described. - When the proceeding enters into the random access, it is examined as to what number of tune is to be accessed by reading information stored in the RAM included in the
system control circuit 23. For example, a sixth tune is determined. Typically, when the user inputs a number allotted to a tune desired to be performed by depressing selected one of ten keys, data representative of the tune number is inputted to the RAM. Therefore, the tune number to be accessed can be determined by reading the RAM. - It is examined as to what absolute time is necessary for the sixth tune to start by reading data stored in the RAM. For example, 16 minutes and 00 second is determined. For determination of the start time, various kinds of data stored in the innermost circumference of the disc as described previously have been read by the
system control circuit 23 and stored in the RAM included therein. - A travelling time for the information reader (pickup) is calculated from the command time and the current time. Form example, x seconds is determined.
- A current value of the revolution number of the motor for disc rotation is held.
- The track servo circuit is disconnected and the pickup is moved for x seconds. Thereafter, the track servo circuit is pulled in.
- A current value of time (absolute value) is read out of the disc when the pickup reaches a desired position. For example, a minutes and b seconds is determined. The absolute value is stored in the signal track.
- It is decided as to whether a minutes and b seconds is greater than 16 minutes and 00 second. If greater, the proceeding proceeds to a step S8 and if smaller, the preceeding branches to a step S10.
- It is decided as to whether the difference from the command time is less than a predetermined value. If "YES", the proceeding proceeds to a step S12 and if "NO", it proceeds to a step S9.
- The track servo circuit is again disconnected and the information reader (pickup) is returned for y seconds. Thereafter, the track servo circuit is pulled in. Subsequently, the proceeding returns to the step S6 and the steps S6, S7, S8 and S9 or the steps S6, S7, S10 and Sll are executed.
- Similar to the steps S8 and S9 and not described.
- The information reader (pickup) is returned by one track.
- A current value of time (absolute time) is read out of the disc.
- It is decided as to whether the current time coincides with the command time. If "YES", normal performance is effected and if "NO", the proceeding returns to the step S12.
- The information reader (pickup) is advanced by one track.
- A current value of time is read out of the disc.
- It is decided as to whether the current time coincides with the command time. If "YES", normal performance is effected and if "NO", the proceeding proceeds to the step S15.
- As described above, in the high rate search (random access) according to the prior art apparatus, the waiting time Tl is required for the motor servo operation, whereby after normal operation is reached, the information including the number of tunes and the absolute time is read to further correct accessing (See Figs. 5A-5D). This correction, as will be seen from the flow chart of Fig. 6, is repeated several times. Consequently, the waiting time Tl for the motor servo operation disadvantageously occupies a large proportion within the entire access time. To reduce the access time, the waiting time Tl must be decreased.
- An object of the present invention is to provide a reproducing rate control apparatus capable of reducing the time for high rate search (random access).
- The present invention is featured by comprising means for predicting a revolution number of a disc at a command position, means for controlling a motor for rotating the disc so that the disc rotates at a predicted revolution number, and means for moving an information reader adapted to read information recorded on the disc to the command position when the revolution number controlling is effected or after the revolution number controlling has been completed, whereby high rate search (random access) for reading a desired kind of information can be effected.
- The present invention is further featured by comprising a disc drive motor revolution number detector, whereby a revolution number detected by the disc drive motor revolution number detector is compared with the predicted revolution number to effect revolution number controlling so that the former revolution number coincides with the latter revolution number.
- In the accompanying drawings:
- Fig. 1 is a block diagram showing a prior art signal reproducing rate control apparatus;
- Figs. 2A and 2B show waveforms in a modulation scheme;
- Fig. 3 is a diagram showing switchover states of selectors shown in Fig. 1;
- Fig. 4 is a graphical representation showing the relation between the radius and the revolution number of a disc;
- Figs. 5A-5D are waveform diagrams useful in explaining the relation between the motor servo mode and the motor revolution number during accessing;
- Figs. 6A and 6B show flow chart illustrative of functions of a system control circuit shown in Fig. 1;
- Fig. 7 is a block diagram of a signal reproducing rate control apparatus according to an embodiment of the invention;
- Fig. 8 is a circuit diagram of a command voltage output circuit;
- Fig. 9 is a similar diagram to Fig. 5 during accessing in accordance with the invention;
- Fig. 10 is a block diagram showing another example of the command voltage output circuit;
- Fig. 11 is a flow chart illustrative of functions characteristic to a system control circuit in the Fig. 7 embodiment;
- Fig. 12 is a block diagram showing another embodiment of the signal reproducing rate control apparatus according to the invention;
- Fig. 13 is a circuit diagram showing still another example of the command voltage output circuit;
- Fig. 14 is a waveform diagram useful in explaining the operation of the Fig. 13 circuit;
- Fig. 15A is a flow chart illustrative of functions characteristic to a system control circuit in the Fig. 12 embodiment;
- Fig. 15B shows an interruption program for use in the flow chart of Fig. 15A; and
- Fig. 16 is a block diagram showing still another embodiment of the signal reproducing rate control apparatus according to the invention.
- Referring now to Fig. 7, there is illustrated a preferred embodiment of a signal reproducing rate control apparatus according to the present invention. In Fig. 7, components corresponding to those in Fig. 1 are designated by identical reference numerals.
Reference numeral 24 designates a command voltage output circuit an example of which is illustrated in Fig. 8. - A command voltage output circuit exemplified in Fig. 8 comprises a plurality of voltage sources Va to V x with preset voltages (also designated by V to V ) and a
switch 25 which is controlled by asystem control circuit 23. Thesystem control circuit 23 includes a ROM stored with a table as shown in Table 1 below and selects a command revolution number in accordance with an absolute time allotted to a command position under random accessing. The preset voltages V , Vb, Vc, ... and Vx supplied from the voltage sources V a to Vx shown in Fig. 8 correspond to revolution numbers 8.0, 6.8, ... and 3.3 rps listed in Table 1. A motor drive voltage approximating a revolution number at a command position is selected by switching over theswitch 25 and applied to amotor 2. - Status of high rate search (access) is illustrated in Fig. 9. In this embodiment, a voltage corresponding to a command revolution number, for example, V is first set prior to effecting high rate search (access) and thereafter, an
information reader 23 is moved for accessing. After the accessing has been completed, the motor servo mode is switched to a start mode, which is followed by a normal mode for normal rotation. This high rate search according to teachings of the present invention is different from the prior art high rate search described with reference to Fig. 5 in that when the start mode is reached, the revolution number has already been in close proximity of the command revoltuion number Vco. Consequently, a time interval T2 required for pulling the motor servo mode into the normal mode can be reduced as compared to the time interval T1 shown in Fig. 5. The time interval T2 can be substantially zeroed if the difference from the command revolution number is allowed to fall within ±5% by increasing the number of the voltage sources shown in Fig. 8. - The command
voltage output circuit 24 may also be constituted by a well known PWM wave generator utilizing a clock pulse and a counter. - Fig. 10 shows an example of the PWM wave generator. A
counter 26 is set by a reference frequency and is preset by a rectangular wave having a fixed period and a duty ratio varying according to an absolute time allotted to a command position. A low-pass filter 19 corresponds to that shown in Fig. 7. - Since the
counter 26 is set by the reference frequency, a signal at a constant frequency is delivered to the low-pass filter 19. However, the duty cycle of a rectangular waveform output from thecounter 26 is varied with the preset value and therefore, a voltage delivered out of the low-pass filter 19 can correspond to the command revolution number allotted to the command random accessing position. - A flow chart as shown in Fig. 11 is illustrative of functions characteristic to the
system control circuit 23 of Fig. 7 and it substitutes for the step S4 between points A and B in the Fig. 6 flow chart. In other words, the function of the Fig. 7 system control circuit can be described by replacing the step S4 in Fig. 6 with steps S20 to S22 in Fig. 11. - As far as the steps Sl to S3 and the steps S5 to S17 in the prior art example of Fig. 6 are concerned, the Fig. 7
system control circuit 23 performs the same functions and only the steps S20 to S22 shown in Fig. 11 will be described below. - A revolution number of the disc corresponding to 16 minutes and 00 second which is read out of the RAM in the step S2 is read out of the ROM included in the
system control circuit 23. For example, 5.6 rps is thus determined. - A value of disc motor drive voltage corresponding to the 5.6 rps revolution number is determined by reading data stored in the ROM. For example, 1.6 V is determined.
- The
switch 25 in Fig. 8 is so transferred as to apply the 1.6 V voltage determined in the step S21 to thedisc drive motor 2. - Fig. 12 shows another embodiment of the apparatus according to the present invention wherein a motor
revolution number detector 30 is added, with the remaining components corresponding to those in Fig. 7 designated by identical reference numerals. - The Fig. 7 apparatus is disadvantageous in that an error in the command revolution number is caused when voltage-revolution number characteristics of the disc motor fluctuate or when the voltage-revolution number characteristics are so affected by disc load characteristics as to vary.
- In order to cancel out the error, in the embodiment shown in Fig. 12, information is inputted to a command
voltage output circuit 24 and thereafter, an output of therevolution number detector 30 is compared with a predicted command revolution number and correction data is fed to the commandvoltage output circuit 24, thereby approximating the motor revolution number to the command revolution number. - Fig. 13 illustrates a command
voltage output circuit 24 suitable for the Fig. 12 embodiment and Fig. 14 illustrates waveforms useful in explaining the operation of the Fig. 13 circuit. - The command
voltage output circuit 24 as shown in Fig. 13 comprises constantcurrent sources system control circuit 23, acapacitor 106, anoperation amplifier 107, and abuffer 108. Themotor 2 is driven by the output from thebuffer 108. An integration amplifier comprised of thecapacitor 106 andoperation amplifier 107 and the two, positive and negative, constantcurrent sources - Detection data from the
revolution number detector 30 shown in Fig. 12 is compared with data of a predicted command revolution number at thesystem control circuit 23. When a revolution number of the motor is smaller than the command revolution number, thesystem control circuit 23 turns on theswitch 104. Then, the output of the ramp function generator, i.e., of theoperation amplifier 107 increases as shown in Fig. 14, which increases the revolution number of themotor 2. Subsequently, when the revolution number ofmotor 2 detected by therevolution number detector 30 reaches the command revolution number, thesystem control circuit 23 turns off theswitch 104. As a result, the output of the operation amplifier is maintained at a constant value. - Conversely, when the revolution number of
motor 2 detected by therevolution number detector 30 is larger than the command revolution number, theswitch 103 is turned on. Theswitch 105 is a switch for resetting the command voltage after a random access has been finished. - Fig. 15A shows a flow chart illustrative of functions characteristic to the
system control circuit 23 of Fig. 12 and the flow chart substitutes for the steps S4 and S5 between points A and C in the Fig. 6 flow chart. In other words, the function of the Fig. 12 system control circuit can be described by replacing the steps S4 and S5 in Fig. 6 with steps S30 to S43 in Fig. 15A. - As far as the steps Sl to S3 and the steps S6 to S17 in the prior art example of Fig. 6 are concerned, the Fig. 12
system control circuit 23 performs the same functions and only the steps S30 to S43 shown in Fig. 15 will be described below. - A revolution number of the disc corresponding to an absolute time of 16 minutes and 00 second which is read out of the RAM in the step S2 is read out of the ROM included in the
system control circuit 23. For example, 5.6 rps is thus determined. - The
selector 38 is transferred to contact b to disconnect the track servo circuit. - The x seconds determined in the step S3 is inputted to a timer included in the
system control circuit 23 which determines a desired travelling time of theinformation reader 32. - The information reader (pickup) is moved.
- Voltage of the
disc drive motor 2 is varied to change the revolution number of themotor 2. - It is decided as to whether the revolution number of the
disc drive motor 2 is 5.6 rps. If "NO", the proceeding proceeds to the step S36 and if "YES", it proceeds to the step S37. - It is decided as to whether the timer is zeroed. The timer is decremented one by one second under an interruption program shown in Fig. 15B. If "YES" indicating that the information reader has moved for x seconds before the revolution number of the disc drive motor reaches 5.6 rps, the proceeding proceeds to the step S39.
- When the revolution number of the disc drive motor reaches 5.6 rps prior to lapse of the x seconds, the proceeding proceeds to this step S37 in which the disc drive motor voltage is fixed.
- It is decided as to whether the timer is zeroed. After lapse of the x seconds, the proceeding proceeds to the step S39.
- The movement of the information reader (pickup) is ceased.
- The track servo circuit is connected.
- It is decided as to whether the revolution number of the disc drive motor is 5.6 rps. If "NO", the proceeding proceeds to the step S42 and if "YES", it proceeds to the step S43.
- Voltage of the disc drive motor is varied.
- The disc drive motor voltage is fixed.
- If the proceeding proceeds to the step S 39 by way of the steps S 34 to S36, there is no chance of fixing the disc drive motor voltage. In this case, fixation of the motor voltage is carried out in the steps S41 to S43. Conversely, if the proceeding proceeds to the step S39 by way of the steps S34, S35, S37 and S38, the disc drive motor voltage is fixed in the step S37 with the result that the voltage fixation is doubled in the step S43. However, such a doubled voltage fixation arises no inconveniences in the operation.
- Fig. 16 shows still another embodiment of the apparatus according to the invention wherein a
position detector 31 for the information reader is added. In CD type discs, it is stipulated that the recording linear velocity falls within a range of from 1.2 m/S to 1.4 m/S. Accordingly, in a disc having information recorded at a linear velocity of 1.2 m/S, the predicted command revolution number deviates from that pursuant to an absolute time-revolution number correspondence table established under a calculation condition of 1.4 m/S. - To cope with this problem, the information
reader position detector 31 detects a disc radius R at a reading position, and a linear velocity v is calculated in accordance with a formula, v = 2πR·f, by using a revolution number f detected by therevolution number detector 30. - Thus, various absolute time-revolution number correspondence tables corresponding to the different linear velocities are stored in advance in the ROM included in the
system control circuit 23 and a correspondence table corresponding to a calculated linear velocity is selected, thereby making it possible to minimize errors in the predicted revolution number due to variations in the linear velocity. - As has been described, according to the present invention, the time for pulling the disc motor mode into the normal rotation after the high rate search (random access) can be minimized and hence the time for the high rate search (random access) can advantageously be minimized.
Claims (7)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP59064/83 | 1983-04-04 | ||
JP58059064A JPS59185071A (en) | 1983-04-04 | 1983-04-04 | Controller of reproducing speed of information recording disc |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0123946A1 true EP0123946A1 (en) | 1984-11-07 |
EP0123946B1 EP0123946B1 (en) | 1988-07-27 |
Family
ID=13102538
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP84103636A Expired EP0123946B1 (en) | 1983-04-04 | 1984-04-03 | Reproducing rate control apparatus for information recording disc |
Country Status (4)
Country | Link |
---|---|
US (1) | US4675855A (en) |
EP (1) | EP0123946B1 (en) |
JP (1) | JPS59185071A (en) |
DE (1) | DE3473076D1 (en) |
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2559936A1 (en) * | 1984-02-20 | 1985-08-23 | Sony Corp | OPTICAL RECORDING DISK DRIVE |
EP0180432A2 (en) * | 1984-11-02 | 1986-05-07 | Sony Corporation | Apparatus for reproducing digital signals |
EP0183554A2 (en) * | 1984-11-28 | 1986-06-04 | Pioneer Electronic Corporation | Video/compact disk player |
WO1986005310A1 (en) * | 1985-03-09 | 1986-09-12 | Deutsche Thomson-Brandt Gmbh | System to ascertain the scanning speed of audio discs with contactless scanning |
EP0196216A2 (en) * | 1985-03-25 | 1986-10-01 | Sony Corporation | Apparatus for reproducing digital signals |
EP0228848A2 (en) * | 1985-12-20 | 1987-07-15 | Sony Corporation | Disc reproducing apparatus |
US4710827A (en) * | 1985-05-29 | 1987-12-01 | Nippon Kogaku K. K. | Servo apparatus |
WO1990013172A1 (en) * | 1989-04-19 | 1990-11-01 | Deutsche Thomson-Brandt Gmbh | Control circuit |
EP0435646A2 (en) * | 1989-12-28 | 1991-07-03 | Sony Corporation | Target track position retrieval device |
US5056076A (en) * | 1986-11-27 | 1991-10-08 | Sharp Kabushiki Kaisha | Method for controlling the rotational velocity of an information recording disk |
US5063550A (en) * | 1988-10-12 | 1991-11-05 | Pioneer Electronic Corporation | Loop-gain control system in a spindle servo loop |
EP0498503A1 (en) * | 1991-01-31 | 1992-08-12 | Deutsche Thomson-Brandt GmbH | Method for the reduction of the access time |
EP0505273A2 (en) * | 1991-03-21 | 1992-09-23 | Lg Electronics Inc. | Apparatus and method for controlling spindle motor of compact disc utilizing appliance |
EP0649131A2 (en) * | 1993-10-07 | 1995-04-19 | Sony Corporation | Servo control system for disk player |
EP0683488A1 (en) * | 1994-05-20 | 1995-11-22 | Mitsumi Electric Company Ltd. | Method of measuring linear velocity of disk |
BE1008963A3 (en) * | 1994-11-18 | 1996-10-01 | Philips Electronics Nv | DISC REGISTRATION CONTAINER, AND RECORDING AND / OR READING DEVICES FOR RECORDING / READING INFORMATION ON / OF THE REGISTRATION CONTAINER. |
EP0772191A3 (en) * | 1995-10-31 | 1997-07-16 | Minebea Co Ltd | Information recording device |
EP0786773A2 (en) * | 1996-01-24 | 1997-07-30 | Sony Corporation | A disc reproducing apparatus and method |
WO1998036413A1 (en) * | 1996-10-25 | 1998-08-20 | Oak Technology, Inc. | Optical disk drive motor servo system and method for closed loop speed control thereof |
US8592524B2 (en) | 2008-01-25 | 2013-11-26 | Exxonmobil Chemical Patents Inc. | Thermoplastic elastomer compositions |
Families Citing this family (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3681501D1 (en) * | 1985-05-29 | 1991-10-24 | Matsushita Electric Ind Co Ltd | SPEED CONTROL DEVICE FOR RECORD CARRIER. |
US4853913A (en) * | 1985-06-17 | 1989-08-01 | Kabushiki Kaisha Toshiba | Pick-up control circuits for disc information reproducing apparatus |
EP0497387B1 (en) * | 1985-07-03 | 2000-01-12 | Pioneer Electronic Corporation | Record information reproducing method with content identifiers |
US4816937A (en) * | 1985-10-17 | 1989-03-28 | Canon Kabushiki Kaisha | Recording and/or reproduction apparatus capable of retaining start up information |
US5016124A (en) * | 1986-01-14 | 1991-05-14 | Canon Kabushiki Kaisha | Recording apparatus with control of energy to the drive at start up |
JPS62259263A (en) * | 1986-05-06 | 1987-11-11 | Pioneer Electronic Corp | Method and device for leading-in of spindle servo |
JP2545809B2 (en) * | 1986-10-09 | 1996-10-23 | ソニー株式会社 | Information signal reproduction device |
JPH0731869B2 (en) * | 1986-10-17 | 1995-04-10 | 株式会社日立製作所 | Disk rotation drive |
JPH01128262A (en) * | 1987-11-13 | 1989-05-19 | Teac Corp | Disk device |
JPH0724142B2 (en) * | 1989-04-28 | 1995-03-15 | 株式会社ケンウッド | Optical disc servo circuit |
US5715157A (en) * | 1989-05-03 | 1998-02-03 | Deutsche Thomson-Brandt Gmbh | Apparatus for braking a spindle motor in a disc playback system |
US5255260A (en) * | 1989-07-28 | 1993-10-19 | Matsushita Electric Industrial Co., Ltd. | Optical recording apparatus employing stacked recording media with spiral grooves and floating optical heads |
KR920003426B1 (en) * | 1989-10-13 | 1992-04-30 | 삼성전자 주식회사 | Over-rotation stop device of spindle motor |
KR930003193B1 (en) * | 1991-01-25 | 1993-04-23 | 삼성전자주식회사 | Unusual circulation preventing circuit of spindle motor |
JP2516053Y2 (en) * | 1991-04-23 | 1996-11-06 | 船井電機株式会社 | Optical disc player |
US5528574A (en) * | 1992-03-09 | 1996-06-18 | Hitachi, Ltd. | Disk reproducing apparatus capable of increasing speed of access to disks recorded at constant linear velocity |
JP3336629B2 (en) * | 1992-06-09 | 2002-10-21 | ソニー株式会社 | Optical disk device and optical pickup moving method |
JP3155663B2 (en) * | 1994-05-23 | 2001-04-16 | アルプス電気株式会社 | Optical disk drive |
JPH087498A (en) * | 1994-06-17 | 1996-01-12 | Hitachi Ltd | Recording information reproducing device |
TW272280B (en) * | 1994-08-08 | 1996-03-11 | Hitachi Seisakusyo Kk | |
US5583841A (en) * | 1995-01-17 | 1996-12-10 | Discovision Associates | Apparatus for improved search on information storage member rotating at constant linear velocity |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0011494A1 (en) * | 1978-11-16 | 1980-05-28 | Discovision Associates | Method and apparatus for controllably rotating an information storage disc |
EP0011493A1 (en) * | 1978-11-16 | 1980-05-28 | Discovision Associates | Method and apparatus for precisely controlling the angular velocity of an information storage disc |
DE3030720A1 (en) * | 1980-08-14 | 1982-03-18 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Synchronous control of magnetic disc recording - has digital synchronous drive to allow constant sampling rate of recorded information |
EP0066445A1 (en) * | 1981-05-29 | 1982-12-08 | Sony Corporation | Servo circuit for use in reproducing PCM signal discs |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3893178A (en) * | 1973-12-19 | 1975-07-01 | Information Storage Systems | Synchronization of multiple disc drives |
US4236050A (en) * | 1978-06-30 | 1980-11-25 | Mca Discovision, Inc. | System for recovering information from a movable information storage medium having a pilot signal with an aligned phase angle in adjacent tracks |
JPS5671856A (en) * | 1979-11-15 | 1981-06-15 | Sony Corp | Playback device of disc |
JPS5764371A (en) * | 1980-09-30 | 1982-04-19 | Toshiba Corp | Rotation control system of disk recording medium |
JPH0616340B2 (en) * | 1981-09-30 | 1994-03-02 | 株式会社日立製作所 | Playback speed controller |
GB2109593B (en) * | 1981-09-30 | 1985-09-04 | Hitachi Ltd | Playback speed control system |
US4450552A (en) * | 1982-03-31 | 1984-05-22 | Rca Corporation | Linear velocity control means |
JPS5956262A (en) * | 1982-09-27 | 1984-03-31 | Toshiba Corp | Disc device |
-
1983
- 1983-04-04 JP JP58059064A patent/JPS59185071A/en active Granted
-
1984
- 1984-04-03 US US06/596,417 patent/US4675855A/en not_active Expired - Lifetime
- 1984-04-03 DE DE8484103636T patent/DE3473076D1/en not_active Expired
- 1984-04-03 EP EP84103636A patent/EP0123946B1/en not_active Expired
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0011494A1 (en) * | 1978-11-16 | 1980-05-28 | Discovision Associates | Method and apparatus for controllably rotating an information storage disc |
EP0011493A1 (en) * | 1978-11-16 | 1980-05-28 | Discovision Associates | Method and apparatus for precisely controlling the angular velocity of an information storage disc |
DE3030720A1 (en) * | 1980-08-14 | 1982-03-18 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Synchronous control of magnetic disc recording - has digital synchronous drive to allow constant sampling rate of recorded information |
EP0066445A1 (en) * | 1981-05-29 | 1982-12-08 | Sony Corporation | Servo circuit for use in reproducing PCM signal discs |
Non-Patent Citations (1)
Title |
---|
Patent Abstracts of Japan vol. 6, no. 82, 20 May 1982 & JP-A-57-18057 * |
Cited By (38)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2559936A1 (en) * | 1984-02-20 | 1985-08-23 | Sony Corp | OPTICAL RECORDING DISK DRIVE |
EP0180432A3 (en) * | 1984-11-02 | 1987-10-07 | Sony Corporation | Apparatus for reproducing digital signals |
EP0180432A2 (en) * | 1984-11-02 | 1986-05-07 | Sony Corporation | Apparatus for reproducing digital signals |
US4855978A (en) * | 1984-11-28 | 1989-08-08 | Pioneer Electronic Corporation | Video/compact disk player having reduced track search time |
EP0183554A3 (en) * | 1984-11-28 | 1987-06-24 | Pioneer Electronic Corporation | Video/compact disk player |
EP0183554A2 (en) * | 1984-11-28 | 1986-06-04 | Pioneer Electronic Corporation | Video/compact disk player |
WO1986005310A1 (en) * | 1985-03-09 | 1986-09-12 | Deutsche Thomson-Brandt Gmbh | System to ascertain the scanning speed of audio discs with contactless scanning |
US4764824A (en) * | 1985-03-25 | 1988-08-16 | Sony Corporation | Dual servo system for rotating tape head control |
EP0196216A3 (en) * | 1985-03-25 | 1987-08-12 | Sony Corporation | Apparatus for reproducing digital signals |
EP0196216A2 (en) * | 1985-03-25 | 1986-10-01 | Sony Corporation | Apparatus for reproducing digital signals |
US4710827A (en) * | 1985-05-29 | 1987-12-01 | Nippon Kogaku K. K. | Servo apparatus |
EP0228848A3 (en) * | 1985-12-20 | 1988-01-07 | Sony Corporation | Disc reproducing apparatus |
EP0228848A2 (en) * | 1985-12-20 | 1987-07-15 | Sony Corporation | Disc reproducing apparatus |
US5056076A (en) * | 1986-11-27 | 1991-10-08 | Sharp Kabushiki Kaisha | Method for controlling the rotational velocity of an information recording disk |
US5063550A (en) * | 1988-10-12 | 1991-11-05 | Pioneer Electronic Corporation | Loop-gain control system in a spindle servo loop |
WO1990013172A1 (en) * | 1989-04-19 | 1990-11-01 | Deutsche Thomson-Brandt Gmbh | Control circuit |
US5298812A (en) * | 1989-04-19 | 1994-03-29 | Deutsche Thomson-Brandt Gmbh | Regulating circuit as for controlling the speed of a motor |
EP0435646A3 (en) * | 1989-12-28 | 1993-03-31 | Sony Corporation | Target track position retrieval device |
EP0435646A2 (en) * | 1989-12-28 | 1991-07-03 | Sony Corporation | Target track position retrieval device |
WO1992014246A1 (en) * | 1991-01-31 | 1992-08-20 | Deutsche Thomson-Brandt Gmbh | Process for reducing access time |
EP0498503A1 (en) * | 1991-01-31 | 1992-08-12 | Deutsche Thomson-Brandt GmbH | Method for the reduction of the access time |
EP0505273A2 (en) * | 1991-03-21 | 1992-09-23 | Lg Electronics Inc. | Apparatus and method for controlling spindle motor of compact disc utilizing appliance |
US5477522A (en) * | 1991-03-21 | 1995-12-19 | Goldstar Co., Ltd. | Apparatus for controlling spindle motor of compact disc utilizing appliance |
EP0505273A3 (en) * | 1991-03-21 | 1993-03-17 | Goldstar Co. Ltd. | Apparatus and method for controlling spindle motor of compact disc utilizing appliance |
US6269061B1 (en) | 1993-10-07 | 2001-07-31 | Sony Corporation | Servo control system for disk player |
EP0649131A2 (en) * | 1993-10-07 | 1995-04-19 | Sony Corporation | Servo control system for disk player |
EP0649131A3 (en) * | 1993-10-07 | 1995-08-16 | Sony Corp | Servo control system for disk player. |
CN1084910C (en) * | 1993-10-07 | 2002-05-15 | 索尼公司 | Servo control system for disk player |
EP0683488A1 (en) * | 1994-05-20 | 1995-11-22 | Mitsumi Electric Company Ltd. | Method of measuring linear velocity of disk |
US5680023A (en) * | 1994-05-20 | 1997-10-21 | Mitsumi Electric Co., Ltd. | Method of measuring linear velocity of disk |
BE1008963A3 (en) * | 1994-11-18 | 1996-10-01 | Philips Electronics Nv | DISC REGISTRATION CONTAINER, AND RECORDING AND / OR READING DEVICES FOR RECORDING / READING INFORMATION ON / OF THE REGISTRATION CONTAINER. |
EP0772191A3 (en) * | 1995-10-31 | 1997-07-16 | Minebea Co Ltd | Information recording device |
US5910934A (en) * | 1996-01-24 | 1999-06-08 | Sony Corporation | Disc reproducing apparatus and method with adjustment of rotation speed between read positions |
EP0786773A3 (en) * | 1996-01-24 | 1998-05-20 | Sony Corporation | A disc reproducing apparatus and method |
EP0786773A2 (en) * | 1996-01-24 | 1997-07-30 | Sony Corporation | A disc reproducing apparatus and method |
WO1998036413A1 (en) * | 1996-10-25 | 1998-08-20 | Oak Technology, Inc. | Optical disk drive motor servo system and method for closed loop speed control thereof |
US5870363A (en) * | 1996-10-25 | 1999-02-09 | Oak Technology, Inc. | Optical disk motor servo and method for closed loop speed control |
US8592524B2 (en) | 2008-01-25 | 2013-11-26 | Exxonmobil Chemical Patents Inc. | Thermoplastic elastomer compositions |
Also Published As
Publication number | Publication date |
---|---|
JPS59185071A (en) | 1984-10-20 |
EP0123946B1 (en) | 1988-07-27 |
JPS6348098B2 (en) | 1988-09-27 |
DE3473076D1 (en) | 1988-09-01 |
US4675855A (en) | 1987-06-23 |
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